example. Scheme 列表平方的结果为 (1 4 9 16)[mce-map]

(run-scheme '((define (map-square xs)
                   (if (null? xs) '()
                       (cons (* (car xs) (car xs)) (map-square (cdr xs)))))
                 (map-square '(1 2 3 4))))

⇒ (1 4 9 16) · checked